fix: `ActiveSupportConcern` recursively checks for `ClassMethod`

[spencewenski]

Motivation

ActiveSupportConcern uses const_defined? to check if ClassMethods exists on a module. By default, const_defined? checks the module and its ancestors for the existence of the constant. This means that const_defined? will return true when a module does not have ClassMethods defined, but one of its ancestors does. This can result in ActiveSupportConcern generating mixes_in_class_methods.*ClassMethods lines for invalid .*ClassMethods modules.

Implementation

const_defined? takes a second parameter that controls whether to include ancestors in the check. Setting this parameter to false to exclude ancestors.

Tests

The first commit in this PR adds a negative test case that should fail with the existing code and pass with the fix from the second commit.

[spencewenski]

Thanks. I'll merge after the linting fix.

This should be fixed now. Thanks!